Given the Jab was well and truly airborne before the 06/24 intersection, is it a reasonable to think the pilot considered any runway beyond the intersection as "unusable" for the purposes of "thou shall not takeoff until crossing traffic is stopped/passed"... Even if the Pawnee hadn't stopped and had rolled through the intersection, the Jab was already airborne and, therefore, had assured separation vertically.
I've done a similar thing at Caloundra - multiple aircraft in the circuit meant I couldn't get a safe gap to enter and backtrack R12, so after waiting at the intersection and realising this, I promptly did a 180, took off on R05 and stayed at 500AGL until well clear of the circuit then climbed to altitude. Positive separation was assured both laterally and vertically from circuit traffic, but on reading "the roolz", technically illegal I guess as I took off from what would be defined as intersecting runways, even though said intersection was behind me...